Stability of epoxidized oils by oxidation and naturalization



United States Patent O M 3,150,153 STAiilLlTY OF EPOXIDIZED OILS BYOXl'DATION AND NATURALEZATION Stuart A. Harrison, Minneapolis, and HarryG. Simmerrnan, St. Paul, Minn asslgnors to General Mills, Inc., acorporation of Delaware No Drawing. Filed June 15, 1962, Ser. No.202,632 7 Claims. (Cl. Zed-348) The present invention relates to aprocess of treating epoxidized oils. More particularly, it relates tosuch a process wherein the heat stability and/or odor of epoxidized oilsis improved by oxidizing and then neutralizing said oils.

Epoxidized oils are particularly valuable as plasticizers for resinssuch as polyvinyl chloride, polyvinyl acetate, copolyrners of vinylchloride and vinyl acetate, polyvinyliclene chloride, polyvinyl butyral,nitrocellulose chlorinated rubber and the like. A wide variety ofarticles (draperies, luggage, handbags, etc.) have been made from suchplasticized materials. It is highly desirable, if not essential, thatsuch plasticized materials and the articles prepared therefrom berelatively heat stable and without offensive odors. However, many of theknown epoxidized oils lack the desired heat stability and/ or haveotfensive odors which undesirable properties are passed on to theresinous materials plasticized with said oils.

We have now discovered that the heat stability and odor of epoxidizedoils can be improved by oxidizing and then neutralizing said oils. Inthis way, the value of the oils as plasticizers is greatly increased.

It is, therefore, an object of the present invention to provide a novelprocess for treating epoxidized oils.

Another object of our invention is to provide a process for improvingthe heat stability and/ or odor of epoxidized oils.

These and other objects will become apparent from the following detaileddescription.

The epoxidized oils which may be treated according to the process of thepresent invention include the aliphatic and cycloaliphatic, aryl andaralkyl esters of epoxy fatty acids, the fatty acid group containingfrom about 8 to 22 carbon atoms. The fatty acid group may be derivedfrom any animal, vegetable or marine oil containing un saturated fattyacid groups; they may be derived from the mixed fatty acids contained insuch oils; or they may be derived from isolated unsaturated fatty acids,either naturally occurring or synthetic. A wide variety of alcohols maybe used for esterification of the described epoxy fatty acids. Thesealcohols include those having a hydrocarbon group attached to thehydroxyl group and include par* ticularly monohydric aliphatic alcoholssuch as methanol, ethanol, propanol, butanol and the like; polyhydricalcohols such as the glycols, diethylene glycol and the like; andglycerols and polyglycerols, etc. The alcohols used for esterificationalso include the aromatic alcohols such as phenol; the aralltyl alcoholssuch as benzyl alcohol; and cycloaliphatic alcohols such ascyclohexanol.

While any of the described oils may be treated by our process, it isparticularly applicable to those prepared from naturally occurring oils,such as soybean oil, which have been epoxidized using non-aqueousperacetic acid as described in the Phillips and Starcher Patent No.2,785,- 185. Such oils have high odor and poor heat stability be lievedto be caused by high acid values. However, mere neutralization of saidoils with caustic, for example, fails to improve the heat stability orodor of said oils. Thus, it is theorized that the oils have a bufferingcapacity probably due to esters and other organic complexes which makesneutralization alone ineffective.

As indicated above, the first step in our process is oxi dation of theepoxidized oils. Any of the conventional 3 ,150,153 Patented Sept. 22,1964 methods for oxidizing organic materials can be employed. Thusoxygen, air or other oxygen containing gas can be bubbled through theoils; or peroxides, such as hydrogen peroxide, can be used to treat theoils. Other oxi dants and oxidation catalysts can be employed as well ascombinations thereof. Obviously, the reaction conditions will varysomewhat with the various oxidizing agents and the particular oils beingoxidized. It is only necessary that the oils be oxidized to a sufficientdegree to facilitate subsequent neutralization with alkaline mate rials.And, of course, the combination of the oxidation and neutralization mustbe sutiicient to improve the heat stability and/ or odor of theepoxidized oils. When using oxygen, air or other oxygen containing gas,the oxidation is preferably carried out at temperatures of about 50 toC. for about one hour to 15 hours or more. Oxida tion with hydrogenperoxide is preferably accomplished at temperatures of about 25 to 150C. for about 30 min utes to five hours or more. It is also preferred touse aqueous hydrogen peroxide (i.e., about 20 to 70% by The oxidationcan be accompanied by or followed by water washing. Thus, the epoxidizedoils can be oxidized and water washed in a series of steps or theoxidation can be completed and then the oxidized oil can be waterWashed. Of course, our process can be carried out with out waterwashing. However, it is preferred to use such treatment to remove someof the oxidation products and/ or lower the acid values of the oxidizedoils to some degree.

After completion of the oxidation or oxidation and water washing steps,the oil is neutralized. Such neutrali zation is preferably carried outby contacting the oxidized oils with aqueous alkali or alkaline earthmetal hydroxides or oxides, such as aqueous sodium hydroxide, potassiumhydroxide, calcium hydroxide and the like. Other alka line treatingagents can also be used, i.e., carbonates, bi carbonates and the like.Again the degree of neutralization is difiicult to define precisely.However, it should be sufficient to lower the acid value appreciably,preferably to 0.1 or less. Additionally, the combination of theoxidation and neutralization steps must improve the heat stabilityand/or odor of the epoxidized oils.

The oxidized and neutralized oil, if necessary, can be water washed,stripped to remove any remaining Water or other volatile materials and/or filtered. The filtration step can be aided by the addition of afilter aid, such as I-lyfio Supercel, Filtrol Grade I, and the like.

The epoxidized oils, treated according to our process, are particularlyuseful as plasticizers for various resinous materials. Such oils haveexcellent heat stability and do not have otiensive odors.

The following examples serve to further illustrate the present inventionwithout limiting the same thereto.

Example I Into a stream cone was placed 300' g. of an epoxidized oilhaving the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.3 Acid value (g. KOH/IOOO g.)0.8 Sap. No 182.4 Viscosity (Gardner) 0 Said oil was prepared bytreating alkali refined soybean oil with non-aqueous peracetic acid. Airwas drawn through the oil for one hour while the cone was heated underfull steam pressure (about 98 0). Then five g. NaOH dis solved inapproximately 50 ml. water was added and the resulting mixture washeated and stirred to effect contact of the NaOH with the air oxidizedoil. After allowing the mixture to stand for approximately 12 hours, the

Color (Gardner) Water was stripped off using a water vacuum pump. To 100g. of the product was added one g. of Filtrol Grade I (an acid activatedmontmorillonite clay). The productfilter aid mixture was then heated for15 minutes on a steam bath and filtered. The resulting epoxidized oilhad virtually no odor and the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.4 Acid value (g. KOH/ 1000 g.)0.06 Sap. No 180.8 Viscosity (Gardner) M-N This example shows that theprocess of our invention can be used to produce an epoxidized oil ofvery low acid value which is substantially odorless. The oil beforetreatment had an offensive odor similar to acetaldehyde.

Example [I To a 30 gal. glass kettle were added 83.0 lb. water and 123.8lb. of an epoxidized oil having the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.9 Acid value (g. KOH/ 1000 g.)0.44 Sap. No 183.8 Water content percent 0.03 Viscosity (Gardner) NColor (Gardner) 1 (1) About 105 lb. water added.

(2) Kettle temperature adjusted to about 8090 C.

(3) Air bubbled into bottom of kettle with agitation for approximately15 minutes.

(4) Oil-water mixture allowed to settle for about one hour.

(5) About 105 lb. water drained oil.

This treatment was repeated times and then 304.6 g. aqueous NaOH (50% byweight NaOH) was added. The mixture was agitated for one hour at 90 C.The acid number was reduced from 0.49 to 0.13. The water was thenstripped from the oil and the oil was filtered with the aid of lb. HyfioSupercel. There was obtained 106.0 lb. epoxidized oil having thefollowing analysis:

Oxirane oxygen percent 6.9 Iodine value 1.6 Acid value (g. KOH/1-000 g.)0.05 Sap. No 180.6 Water content percent 0.06 Viscosity (Gardner) MColor (Gardner) 1 The treated epoxidized oil also was substantially odorfree. The heat stability of the epoxidized oil before and aftertreatment by our process was also measured by heating the respectivesamples for two hours at 350 F. and also 'for 16 hours at 165 C. Resultsare as follows:

Two hours at Sixteen hours at Untreated Treated Untreated TreatedOxirane Oxygen, percent- 1 6. Color, percent Transfer 37.

The data of this example clearly shows that the heat 4 stability andodor of epoxidized oils can be materially improved by the process of thepresent invention.

Example III To a flask fitted with a stirrer and thermometer were added124 g. aqueous H 0 (30% by weight) and 1000 g. of an epoxidized oilhaving the following analysis:

Oxirane oxygen percent 7.0 Iodine value 2.0 Acid value (g. KOH/IOOO g.)0.57 Sap. No 181.0 Water content percent 0.03 Viscosity (Gardner) LColor (Gardner) 1 Said oil was prepared by treating salad-grade soybeanoil with non-aqueous peraeetie acid. The mixture was stirred for 2 /2hours at a temperature of 60 C. One 1. of water was then added, thestirring was continued for an additional 1 /2 hours, and then thereaction mixture was transferred to a separatory funnel and allowed tostand for about 12 hours. Approximately one 1. of water was drained oiland then the oil was Washed two more times using one 1. of fresh waterfor each wash. The bulk of the water was removed after the third washand two g. caustic soda was added to the oil phase. Afterneutralization, the oil was again washed with one 1. of water andstripped at 60 C. with a water jet in a falling film evaporator. The oilwas then filtered (added 50 g. Hyflo Supercel). The product had thefollowing analysis:

Oxirane oxygen percent 6.8 Iodine value 1.8 Acid value (g. KOH/ 1000 g.)0.0 Sap. No. 180.3 Water content percent 0.11 Viscosity (Gardner) 0 Theabove example shows that the epoxidized oil can be oxidized by H 0 andthat subsequent neutralization will lower the acid value to 0.0.Additionally the treated oil had no offensive odors.

Example IV Two hundred and three lbs. of the same epoxidized oil treatedin Example III and 22 lb. aqueous H 0 (35% by weight) were added to agallon kettle. The reaction mixture was heated to 58 C. with agitation.After 1 /2 hours, 200 lb. Water (temperature 57 C.) was added. Thekettle was allowed to stand overnight and then enough Water to fill thekettle was added. Most of the water was drained off after a settlingperiod of about three hours and the oxidized oil was washed four moretimes by adding water to fill the kettle, allowing the mixture to settleand draining off the Water. The oil was neutralized by adding 181.6 g.NaOl-l (equal amount of water) and agitating the mixture for tenminutes. About 900 lb. water was added at 60 C. This wash water wasdrained oil, the oil was stripped at 68 C. under vacuum and thenfiltered. There was obtained 179 lb. of treated epoxidized oil havingthe following analysis:

Oxirane oxygen percent 7.0 Iodine value 2.1 Acid value (g. KOH/ 1000 g.)0.08 Sap. No. -I 181.0 Water content percent 0.1 Viscosity (Gardner) PColor (Gardner) 1 The oil had a materially improved odor and had heatstability properties similar to the oil of Example II.

It is to be understood that the invention is not to be limited to theexact details of operation or the exact compositions and materialsdescribed, as obvious modifications and equivalents will be apparent tothose skilled in the art and the invention is to be limited only by thescope of the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. The process comprising oxidizing an oil consisting essentially ofesters of epoxidized fatty acids derived from unsaturated fatty acidscontaining from about 8 to 22 carbon atoms and neutralizing theresulting oxidized oil With an aqueous alkaline material, the oxidizingand subsequent neutralizing being sufficient to improve the heatstability and odor of the oil.

2. The process of claim 1 wherein the oxidizing is accomplished by theuse of at least one oxidizing agent selected from the group consistingof oxygen, free oxygen containing gases and peroxides.

3. The process of claim 2 wherein the oxidizing agent is air and theoxidation is carried out at temperatures of about 50 to 150 C. for about1 to 15 hours.

4. The process of claim 2 wherein the oxidizing agent is hydrogenperoxide and the oxidation is carried out at temperatures of about 25 to150 C. for about 30 minutes to 5 hours.

5. The process of claim 1 wherein the neutralizing is accomplished bythe use of an aqueous alkaline material containing at least oneneutralizing agent selected from the group consisting of alkali metalhydroxides, alkaline earth metal hydroxides and alkaline earth metaloxides.

6. The process of claim 1 wherein at least one water washing step isemployed at some point in the process subsequent to the oxidizing step.

7. The process comprising oxidizing epoxidized soybean oil, said oilhaving been prepared by reacting soybean oil with non-aqueous peraceticacid, and neutralizing the resulting oxidized oil with an aqueousalkaline material, the oxidizing and subsequent neutralizing beingsufiicient to improve the heat stability and odor of the epoxidizedsoybean oil.

References Cited in the file of this patent UNITED STATES PATENTS2,810,733 Greenspan Oct. 22, 1957 2,822,368 Rowland et a1 Feb. 4, 19582,956,975 Greenspan Oct. 18, 1960 3,040,076 Seidel et a1. June 19, 1962FOREIGN PATENTS 757,407 Great Britain Sept. 19, 1956 847,343 GreatBritain Sept. 7, 1960 OTHER REFERENCES Greenspan et al.: Ind. Eng. Chem,vol. 45, pages 2722 26 (1953).

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0 3 150,153 September 22 1964 Stuart A. Harrison et a1,

n the above numbered pat rtifiedthat error appears i rs Patent shouldread as It is hereb ce tion and that the said Lette ent requiring correocorrected below.

In the heading to the printed specification lines 2 and "STABILITY OFEPOXIDIZED OILS BY 3 title of invention, for OXIDATION ANDNATURALIZATION" read STABILIZATION OF EPOXIDIZED OILS BY OXIDATION ANDNEUTRALIZATIO column :2

line 56 for "stream" read steam Signed and sealed this 12th day ofJanuary 1965.

(SEAL) Attest:

EDWARD J. BRENNER ERNEST W. SWIDER Attesting Officer Commissioner ofPatents

1. THE PROCESS COMPRISING OXIDIZING AN OIL CONSISTING ESSENTIALLY OFESTERS OF EPOXIDIZED FATTY ACIDS DERIVED FROM UNSATURATED FATTY ACIDSCONTAINING FROM ABOUT 8 TO 22 CARBON ATOMS AND NEUTRALIZING THERESULTING OXIDIZED OIL WITH AN AQUEOUS ALKALINE MATERIAL, THE OXIDIZINGAND SUBSEQUENT NEUTRALIZING BEING SUFFICIENT TO IMPROVE THE HEATSTABILITY AND ODOR OF THE OIL.